dcausse added a comment.
Yes the issue with blank nodes is that they are not "reference-able" and thus point delete queries are impossible which is what we want to achieve with the next gen updater. I did some tests and isBlank is a lot faster (I suppose because this information is inlined as opposed to the IRI that has to be fetched from its dictionary). So materializing the unknown value with the statement identifier we risk to encounter timeouts more frequently. So unless we have a third alternative we have two choices: - use a constant value: probably very fast but we now say: all unknown values are equal. - use the statement identifier: very close to the previous semantic but a lot slower I think I prefer the first approach you suggested, dealing with perf issues seems more annoying than a less precise graph. The usecases that I can think of that could be affected are: - queries based on equality: find entities which share the same value. Such queries will have to filter out explicitly the "unknown value" - queries based on the number of unknown values on a particular property? Examples would help here I think. - other usecases? TASK DETAIL https://phabricator.wikimedia.org/T244341 EMAIL PREFERENCES https://phabricator.wikimedia.org/settings/panel/emailpreferences/ To: dcausse Cc: Lucas_Werkmeister_WMDE, Aklapper, dcausse, darthmon_wmde, Nandana, Lahi, Gq86, GoranSMilovanovic, QZanden, EBjune, merbst, LawExplorer, _jensen, rosalieper, Scott_WUaS, Jonas, Xmlizer, jkroll, Smalyshev, Wikidata-bugs, Jdouglas, aude, Tobias1984, Manybubbles, Mbch331
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